Lundi is a young boy who lives with his aunt and uncle in Switzerland in the early 1930s. One day while walking around the Alps, Lundi finds a little girl who is the only survivor of a plane crash and has lost all her memories. She is named Jeudi by his uncle and both of them are raised together. As they grow up together, Jeudi and Lundi develop a deep friendship for each other. A few years later Jeudi wants to find her past. Her only clue is a song that she is constantly hearing in her head, a song called Alpen Rose. At the time of World War II, Jeudi and Lundi set on a journey to discover Jeudi's past and in the process learn the depth of the love they have for each other.
- Lundi (means Monday in French)
- Jeudi (means Thursday in French)
- Printemps (means spring in French) a cockatoo
The manga series was originally serialized in Japan, in 1983, in the weekly publication Ciao Magazine by Shogakukan, with the first volumen of the series been released in October 1983. The second, third, and fourth followed in February 1984, July 1984, and November 1984. And from then on chapters of the story were released spereodically over the next three years with volumes of the manga series been released in a 3 to 6 months period. The series was finished in late 1986 finishing the storyline in nine small volumens of approximately 180 pages. The remaining volumes (5, 6, 7 8, and 9) were released in February 1985, July 1985, December 1985, June 1986, and September 1986. The manga series was reissued 1993 by Shogakukan through the publishing branch Flower Comics Wide Magazine. This new version of the series was released in four large volumes of at least approximately 350 pages. This new version included new covers, colored pages in each volume as well was pin-ups at the end of the volumes. More recently the series was reissued in Japan in 2000 in four volumens by Flower Comics DeLuxe with different covers which were a combination of black and white photos of different parts of Paris, France with picture of the main characters of the series in the center. As of November 2009 the series has yet to be released in outside of Japan.